package com.graduation.smartparkingplatform.Utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.UnsupportedEncodingException;
import java.util.StringTokenizer;

public class IpDBUtil {
  private static final Logger log = LoggerFactory.getLogger(IPAddressUtils.class);
  private static StringBuilder sb = new StringBuilder();

  /**
   * 从ip的字符串形式得到字节数组形式
   *
   * @param ip 字符串形式的ip
   * @return 字节数组形式的ip
   */
  public static byte[] getIpByteArrayFromString(String ip) {
    byte[] ret = new byte[4];
    StringTokenizer st = new StringTokenizer(ip, ".");
    try {
      ret[0] = (byte) (Integer.parseInt(st.nextToken()) & 0xFF);
      ret[1] = (byte) (Integer.parseInt(st.nextToken()) & 0xFF);
      ret[2] = (byte) (Integer.parseInt(st.nextToken()) & 0xFF);
      ret[3] = (byte) (Integer.parseInt(st.nextToken()) & 0xFF);
    } catch (Exception e) {
      log.error("从ip的字符串形式得到字节数组形式报错" + e.getMessage(), e);
    }
    return ret;
  }

  /**
   * 字节数组IP转String
   *
   * @param ip ip的字节数组形式
   * @return 字符串形式的ip
   */
  public static String getIpStringFromBytes(byte[] ip) {
    sb.delete(0, sb.length());
    sb.append(ip[0] & 0xFF);
    sb.append('.');
    sb.append(ip[1] & 0xFF);
    sb.append('.');
    sb.append(ip[2] & 0xFF);
    sb.append('.');
    sb.append(ip[3] & 0xFF);
    return sb.toString();
  }

  /**
   * 根据某种编码方式将字节数组转换成字符串
   *
   * @param b 字节数组
   * @param offset 要转换的起始位置
   * @param len 要转换的长度
   * @param encoding 编码方式
   * @return 如果encoding不支持，返回一个缺省编码的字符串
   */
  public static String getString(byte[] b, int offset, int len, String encoding) {
    try {
      return new String(b, offset, len, encoding);
    } catch (UnsupportedEncodingException e) {
      return new String(b, offset, len);
    }
  }
}
